Apichaya's place is well located in Sukhumvit and has everything you need for a short stay in Bangkok. It was a bit of a back and forth for me with the planning, which was no problem with Apichaya and we could easily find a solution.
I only stayed at the Della for a night but I can only recommend it. Also, if you're ever in Koh Tao definitely check out The Dearly. The staff is just the loveliest, everything is really personal and whole space is super beautiful and stylish.